Mr Bettel infuriated many Conservatives after going ahead with a press conference on Monday alongside an empty podium where Mr Johnson had been supposed to be addressing the media.
He was accused by some Tories of ‘grandstanding’, and Mr Kawczynski said the scenes only underlined the need for Britain to get out of the “artificial arrogant EU structure” as quickly as possible.
He tweeted: “Luxembourg PM representing a nation smaller than Birmingham admonishing and being disrespectful to a British PM for trying to fulfil will of British people. We need to pull out of EU on October 31 without doubt!”
“We fund the EU to the tune of billions every year not sure what Luxembourg’s contribution has been.”
Conduct of Luxembourg PM towards our Prime Minister today only accentuates the need for us to pull out of this artificial arrogant EU structure as quickly as possible. We fund the EU to the tune of billions every year not sure what Luxembourg’s contribution has been.— Daniel Kawczynski (@DKShrewsbury) September 16, 2019
This afternoon Mr Kawczynski tweeted Mr Bettel, saying "Your conduct yesterday @Xavier_Bettel towards our Prime Minister fell far short of normal diplomatic protocols. Your student theatrical politics demeans your office and country. Hope you are man enough to apologise."
Amid chaotic scenes outside Luxembourg’s Ministry of State yesterday, Mr Johnson walked out complaining a noisy anti-Brexit demonstration made it impossible to go ahead.
To cheers from the crowd, Mr Bettel then mounted an emotional onslaught, complaining the future of citizens across the EU was being held hostage for “party political gains”.
British officials were said to have asked for the press conference to have been moved inside, only to be told there was insufficient space to accommodate all the journalists present.
Former Brexit minister David Jones said Mr Bettel had made a “big mistake” which would appal many of his own people.
“I have no doubt that very many Luxembourgers are dismayed by their Prime Minister’s extraordinary behaviour,” he tweeted.
Even some pro-EU MPs supported Mr Johnson’s decision to walk out.
Sir Nicholas Soames, one of 21 MPs to have the Conservative whip removed by Mr Johnson for rebelling over Brexit, accused Mr Bettel of “unhelpful grandstanding”.
“Very poor behaviour by Luxembourg. Boris Johnson quite right not to be made a fool of,” he tweeted.
Conservative former defence minister Tobias Ellwood agreed that Mr Johnson had been right to “duck out” of the press conference.
“You saw the atmosphere outside the meeting. It is a bit like trying to conduct a press conference outside the Red Lion in Parliament Square,” he told BBC2’s Newsnight.
“It is the not the appropriate place to do it and I am sorry the choreography wasn’t better handled.”
At the same time, however, he acknowledged that Mr Bettel was giving voice to a widely-felt frustration over the continuing Brexit deadlock.
“Xavier Bettel illustrated the frustration that we are all feeling. It is three years since the referendum and we are still trying to secure a deal,” he said.
The row erupted as the UK’s highest court prepared to consider whether Mr Johnson’s five-week suspension of Parliament was lawful.
The Supreme Court in London will hear appeals from two separate challenges brought in England and Scotland to the prorogation of Parliament over three days, starting on Tuesday.
Mr Johnson, who also met European Commission president Jean-Claude Juncker on Monday, insisted a deal was still possible before the UK is due to leave the EU on October 31.